The invention relates to antiperspirant or deodorant compositions intended for topical application to human skin. In particular, it relates to antiperspirant or deodorant compositions comprising an agent that is capable of ameliorating or controlling skin irritancy.
In many countries, civilised behaviour encourages people to take steps to prevent or control body odours or visible wet patches caused by sweating, particularly in the underarm or on clothing in the vicinity of the underarm. People in some countries prefer to control both sweat and odour, whereas in other countries control of odour alone is favoured.
The antiperspirant market is currently dominated by topically applied products based on aluminium or zirconium salts which are intended to prevent, or at least control, localised perspiration at the skin surface, particularly on the underarm. Such formulations can often simultaneously provide a perceived degree of deodorancy.
In contrast, deodorants are formulations that are designed either to mask malodour or to prevent or hinder its formation. The latter method usually comprises reducing and/or controlling the re-growth of the local micro-organism populations, or targeting preferentially those bacteria such as a sub-class of Coryne bacteria which contribute disproportionately to axillary odour generation, or interrupting the pathways by which malodours are formed from secretions.
Antiperspirant and deodorant formulations are utilised in many applicator forms e.g. roll-ons, creams or soft solids, gels, firm sticks, aerosols and pump sprays. However all forms can suffer from a number of common disadvantages.
A principal disadvantage of many deodorants and antiperspirants is that they contain one or more commonly employed ingredients which are perceptibly unfriendly to human skin in those areas of the body to which the formulations are normally applied. Such ingredients are usually employed because they demonstrate other attributes which are advantageous or otherwise render the formulation particularly effective. Such essential or otherwise highly desirable ingredients include liquid carriers such as volatile silicones and ethanol, and indeed many deodorant or antiperspirant actives as well as a host of other ingredients commonly employed in deodorant and antiperspirant formulations. Such ingredients are perceived to exhibit an adverse effect, in particular an irritant effect, on a user""s skin following application. Of those ingredients, particular attention may be accorded to aluminium and zirconium salts and complexes that act as antiperspirants.
Physiologically, irritation in the underarm usually adopts either or both of two forms, which are not mutually exclusive. It can manifest itself as redness due to inflammation or as noxious somatosensory responses such as pruritus (itch), sting and/or burn.
Skin unfriendliness can be tolerated, at least to some extent, which will vary from user to user, but it would be advantageous to identify means of reducing or eliminating the effect. Manifestly, irritation can be ameliorated by lowering the amount of any offending active ingredient in the formulation, but a serious drawback of such an approach is that the efficacy of the ingredient would be impaired.
Rather than look only empirically for materials which can demonstrate skin benefits in an antiperspirant or deodorant formulation, the inventors of the present invention have investigated mechanisms within skin cells which generate irritancy and related adverse skin conditions in humans and have sought means to alleviate or control those mechanisms.
Mankind has sought therapeutic means to relieve pain and suffering ever since records have been kept. Early remedies involved the administration of natural products, commonly by ingestion, topical application or inhalation, presumably as a result of empirical observations. For example, Cannabis sativa, colloquially called cannabis, or extracts therefrom, has been employed therapeutically for approximately 3000 years, being first mentioned in the time of Emperor Shen Nung in the Chinese Compendium of Medicine. It has subsequently been suggested that its perceived efficacy can be due to the action of xcex949-tetrahydrocannabinol. Cannabinoid agents have been asserted to have anti-inflammatory actions (A. W. Wirth et al., Life Sci. 26, 1991-1995 (1980)). More recent research has shown that the biological actions of cannabis are mediated by two similar, but distinct, types of membrane receptor which have been termed Cannabinoid Receptor 1 (CB1R) and Cannabinoid Receptor 2 (CB2R) (Matsuda et al, Nature 346, 561-564 (1990), Munro et al, Nature, 365, 61-65 (1993)).
CB1R is by far the predominant form in the central nervous system, whereas both CB1R and CB2R are located in the peripheral tissues, including the skin. Some investigations have been made to locate natural endogenous ligands that can activate one or other of these receptors. Herein a reference to a CBR activator includes either or both CB1R and CB2R activators.
Arachidonylethanolamide (anandamide) has been stated to exhibit a greater affinity for the CB1R compared with CB2R and is believed to be the endogenous CB1R agonist (Pertwee et al, Br. J. Pharmacol. 105, 980-984 (1992)). It has been suggested that palmitoylethanolamide and 2-arachidonyl-glycerol are putative CB2R agonists (Facci et al, Proc. Natl. Acad. Sci. 92, 3376-3380 (1995), Sugiura et al., J. Biol. Chem. 275, 605-612 (2000)). Ligands that activate both CB1R and CB2R have been shown to be analgesic, whether applied systemically or cutaneously (Calignano et al, Nature,394, 277-280 (1998)).
Therapeutic uses have already been contemplated involving CBRs. For example, U.S. Pat. No. 5,990,170 (Della Valle et al) teaches the therapeutic use of a range of selected mono and dicarboxylic acid amides which bind the CB2R in order to treat diseases connected with this receptor. EP-A-550006 (Della Valle et al) teaches that a range of N-acyl derivatives of amino alcohols to be used for the treatment of pathologies characterised by the degranulation of mast cells. U.S. Pat. No. 5,679,667 describes the use of amino alcohols-N-acyl derivatives as therapeutic agents against neurogenic endoneural edema of the peripheral nerve. However, none of these references disclose or contemplate in any way antiperspirant or deodorant formulations or the use of any of the actives disclosed therein in such formulations.
During the last century, many different classes of compounds have been proposed in patent or other publications for incorporation in antiperspirant or deodorant formulations. However, none of such antiperspirant or deodorant publications have disclosed the subject of the present invention, either knowingly or unwittingly, for example because the compounds that are disclosed in them for other purposes are inactive for the present purpose, even though some of them may be chemically related to an active compound. Alternatively, the selection of ingredients of the instant invention has not been disclosed.
Thus, for example, U.S. Pat. No. 4,781,917 (Luebbe et al) describes the use of different monoethanolamides such as coconut mono- or stearamide monoethanolamide in antiperspirant gel sticks that do not exhibit the advantageous properties required for the instant invention. In addition, U.S. Pat. No. 5,407,668 (Kellner) teaches of the use of a class of alkanolamides in clear deodorant stick compositions as a component of a clarity enhancing solubilizer system, but does not contemplate expressly the presence of aluminium or zirconium antiperspirant salts or complexes. Accordingly, ""668 does not teach how to select materials to satisfy the instant invention.
According to the invention there is provided an antiperspirant or deodorant cosmetic composition suitable for topical application to the human skin, characterised by comprising:
i. an antiperspirant or deodorant active comprising an aluminium and/or zirconium salt or complex;
ii. a carrier for the antiperspirant or deodorant active; and
iii. an effective amount of a CBR activating agent.
By the employment of a CBR activating agent in an effective amount in an antiperspirant or deodorant formulation containing an aluminium and/or zirconium salt or complex, it is possible for users of such formulations to experience reduced or no irritancy such as itch or like skin complaints on areas of the skin to which formulation has been applied.
The capability of a compound to act as a CBR activating agent can be determined using a topical application test on human skin in which the irritant effect of a predetermined concentration of a known irritant, for example a known pruritic agent, such as histamine, is counteracted by chosen amounts of the target compound.
The present invention relates to the incorporation of a CBR activating agent in antiperspirant or deodorant compositions. The effectiveness of a material to act as a CBR activating agent can be determined by incorporating it in an antiperspirant or deodorant composition and observing the extent to which redness, itch, sting or burn is diminished.
It can be convenient to employ a topical application test as a way of demonstrating whether the test material would be effective as a CBR activating agent. In one such test employing the control conditions described subsequently herein, human skin is contacted with a control or test material under a water-impermeable patch for a specified length of time, such as 24 hours and then challenged with a predetermined dose of a known irritant such as histamine applied by iontophoresis at a specified current for a specified period, e.g. 10 seconds at 50 xcexcA, which is counteracted by application of a test material within a range of concentrations so as to be able to identify that at which the material becomes effective. By plotting the perceived strength of the response against time, a test value can be obtained which comprises the area under the curve. This area is normally that from time 0 to 5 minutes and the base line at 0 to the response curve. In an alternative, but related, test procedure, a cream formulation is applied topically to the skin, for example for a period of 4 hours rather than being covered by a patch, and is then challenged in the same way.
The measured activity of test material can vary between subjects. Accordingly, an averaged result should be employed. The test material can be considered to pass the histamine test at its chosen concentration when the averaged test value from histamine plus the test material is less than 80% of the control test value, i.e. that obtained from histamine without the test material under the same test conditions. Preferably, the material and its amount are chosen in combination such that the resultant averaged test value is not higher than 50% of the control test value.
In such a test, the difference necessary for it to be statistically significant decreases as the number of subjects in the test increases. For the most effective CBR activating agents, a small number of subjects can demonstrate a positive result, whereas for less active agents, it is desirable to employ a larger number such as at least 20 subjects and preferably about 50.
Herein a material is considered to be a CBR activating agent, if it passes the foregoing test or any other test method for CBRs described herein.
It is particularly desirable to identify and employ a compound that can act as an activating agent for a CBR ie for either or both CB2R and CB1R, on account of the presence of both CB1R and CB2R sites in skin.
Examples of CBR activating agents (iii) include:
2-arachidonyl-glycerol
1-arachidonyl-glycerol
3-arachidonyl-glycerol
2-linoleoyl-glycerol
2-linolenoyl-glycerol
2-eicosatrienoyl-glycerol
2-eicosatetraenoyl-glycerol
2-eicosapentenoyl-glycerol
2-eicosahexaenoyl-glycerol
Palmitoylethanolamide
(6aR)-trans-3-(1,1-Dimethylheptyl)-6a,7,10,10a-tetrahydro-1-hydroxy-6,6-dimethyl-6H-dibenzo[b,d]pyran-9-methanol, sometimes called HU-210 herein;
Indomethacin morpholinylamide sometimes abbreviated to IMMA herein;
mesylate: (R)-(+)-[2,3-Dihydro-5-methyl-3-(4-morpholinylmethyl)pyrrolo[1,2,3-de]-1,4-benzoxazin-6-yl]-1-naphthalenylmethanone, sometimes called WIN55212-2 herein; (xe2x88x92)-cis-3-[2-Hydroxy-4-(1,1-dimethylheptyl)phenyl]-trans-4-(3-hydroxypropyl) cyclohexanol, sometimes called CP55940 herein;
R-(+)-Methanandamide: [R-(all-Z)]-N-(2-Hydroxy-1-methylethyl)-5,8,11,14-eicosatetraenamide;
Arachidonyl-2xe2x80x2-chloroethylamide: (all Z)-N-(2-cycloethyl)-5,8,11,14-eicosatetraenamide);
Arachidonylcyclopropylamide: (all Z)-N-(cyclopropyl)-5,8,11,14-eicosatetraenamide;
It will understood that, for example, although palmitoyl ethanolamide acts as a CBR activating agent, ethanolamides which are structurally similar, but derived from related aliphatic acids such as stearic acid or linoleic acid do not act as CBR activating agents, even though for various other purposes they would be classified within the same generic class.
Naturally occurring precursors of said CBR activating agents can also be employed herein, generating the activating agent for example by hydrolysis on the skin.
Mixtures of two or more of said can be employed herein, such as a combination of palmitoylethanolamide with an aforementioned glycerol derivative, for example in a weight ratio of from 10:1 to 1:10.
The amount of CBR activating agent (iii) in the invention compositions is preferably selected in the range of from at least 0.05%, and often to not more than 20%, more preferably in some embodiments from 0.1% and in those or other embodiments up to 10%, as herein being by weight based on the formulation or base formulation, as the case may be, unless otherwise stated. In a number of practical formulations, the concentration of CBR activating agent is not more than 5%, and particularly from 0.25 to 2 wt %.
An antiperspirant composition according to the invention comprises an antiperspirant active comprising an aluminium and/or zirconium salt or complex (i). The proportion of antiperspirant active present in the composition according to the invention may be from 1-35% by weight of the composition, preferably at least 5% by weight and more preferably 15-30% by weight of the base composition. A base composition herein excludes any propellant which may be employed.
Examples of suitable actives (i) include aluminium salts, zirconium salts, aluminium and/or zirconium complexes, for example aluminium halides, aluminium hydroxy halides, zirconyl oxyhalides, zirconyl hydroxyhalides, and mixtures thereof. Specific examples include activated aluminium chlorohydrate, aluminium chlorohydrate, aluminium pentachlorohydrate and aluminium zirconium chlorohydrate. Useful zirconium salts include zirconium hydroxy-chloride and zirconium oxychloride. Other generally used actives will be known to those skilled in the art. Preferred actives include ZAG (Zirconium Aluminium Glycine), AAZG (Activated Aluminium Zirconium Glycine), and AACH (Activated Aluminium Chorohydrate). The antiperspirant active can be present in particulate form whereupon it is normally suspended in a suitable carrier fluid, which usually is water-immiscible, and which can be structured or thickened. Alternatively the active can be dissolved in a polar solution, such as for example in aqueous solution or in a polar low weight polyhydric alcohol such as propylene glycol, advantageously 30 to 60% by weight solution.
It is a benefit of the present invention that incorporation of a CBR activating agent in an effective amount can improve the acceptability of conventional antiperspirant-containing formulations, such as those containing an astringent antiperspirant active, by reducing the risk of irritancy.
The deodorant compositions according to the present invention normally comprise 0.01 to 90% of a deodorant active. Deodorancy can be provided by the aforementioned aluminium and/or zirconium antiperspirant salts or complexes, optionally with an additional deodorant active, such as any deodorant active known in the art such as alcohols, in particular aliphatic monohydric alcohols such as ethanol or propanol, antimicrobial actives such as polyhexamethylene biguanides eg those available under the trade name Cosmocil(trademark) or chlorinated aromatics, eg triclosan available under the trade name Irgasan(trademark), non-microbiocidal deodorant actives such as triethylcitrate, bactericides and bacteriostatis. Yet other deodorant actives can include zinc salts such as zinc ricinoleate.
The antiperspirant active salt or complex (i) and the CBR activating agent (iii) can conveniently be employed in a weight ratio of from 1:1 to 100:1, often at least 5:1, and in many instances up to 50:1.
The carrier material for the compositions according to the invention can comprise one or more of volatile carrier fluids, one or more of non-volatile emollients, and it can be structured or thickened by one or a combination of thickener and/or structurant materials if required. The carrier material, including, where relevant, carrier materials providing additional properties such as emolliency, can often comprise up to about 99 wt %, in many instances from 5 to 90 wt % and particularly from 10 to 70 wt % of the composition, or of the base composition, if mixed subsequently with a propellant. Where the composition comprises both hydrophilic and hydrophobic phases, the weight ratio of the two phases is often in the range of 10:1 to 1:10. Aerosol compositions according to the present invention can conveniently be obtained by introducing a base formulation as described herein that is free from propellant and at least 0.7 times and often 1.5 to 20 times its weight of propellant into a suitable aerosol dispenser.
The antiperspirant or deodorant composition can comprise a mixture of particulate solids or a suspension of solids in a liquid medium, which can be thickened to reduce the rate of segregation or structured to produce a cream (soft solid) or solid. Alternatively the composition can comprise a mixture of liquid constituents, including a solution of an active in a carrier, such a composition often adopting the form of an oil-in-water or water-in-oil emulsion, which may be thickened or gelled.
The carrier material, which may be a fluid or a mixture of fluids, is often selected according to the physical form of the cosmetic composition, e.g. volatile low viscosity silicones, low molecular weight hydrocarbons, alcohols and water, and can be selected by those skilled in the art to provide appropriate physical and sensory properties for the product. It will be understood that certain fluid alcohols such as in particular ethanol can constitute both a carrier and a deodorant active simultaneously, though advantageously formulations containing such a material also contain an additional deodorant and/or antiperspirant active.
Volatile silicones are usually selected from cyclic polysiloxanes containing from 3 to 8 dialkylsilicone groups, especially dimethylsilicone groups and particularly 4 or 5 dimethylsilicone groups. Other useful volatile silicones can comprise linear polysiloxanes, preferably containing 4 or 5 alkylsiloxane groups, including terminal groups. Low molecular weight liquid hydrocarbons can comprise paraffin oils. Suitable alcohols can comprise monohydric alcohols, such as C3 to C10 aliphatic alcohols, dihydric alcohols such as glycol or propylene glycol or polyhydric alcohols such as glycerol or sorbitol. Carrier materials can provide additional desirable properties, such as polyhydric alcohols for example glycerol can act as a moisturising agent and volatile cyclomethicones can act as emollients.
The non-volatile emollient, if used in the composition, may consist of a single emollient compound or a mixture of emollients. Such emollients often have a solubility parameter of below 10 and many of from 5.5 to 9. They can typically include saturated fatty acids and fatty alcohol esters, ethers containing aliphatic and a polyalkylene group, hydrocarbons, water insoluble ethers, mineral oils and polyorganosiloxanes, and mixtures thereof.
Non-volatile silicones are often polyalkylsiloxanes, polalkylarylsiloxanes or polyethersiloxanes having a viscosity of above 10 mPa.s, such as up to about 5xc3x97106 mPa.s at 25xc2x0 C., including polymethylphenylsiloxanes or dimethylpolyoxyalkylene ether copolymers.
Emollient aliphatic esters, often containing from about 12 to 25 carbons, and preferably one substituent containing a chain of at least 12 carbons. Examples include cetyl palmitate, butyl myristate, glyceryl stearate and propylene glycol monolaurate. The composition cam comprise a liquid aliphatic ether which can provide emolliency, such as ethers derived from polyalkyene glycols and a low weight (eg up to C6) alcohol, such as polypropylene glycol (10-15) butyl ether.
The total amount of emollient materials within the composition is often within the range of from 1 to 70 wt %.
The thickening or structurant agent, when required, is selected according to the product form of the cosmetic composition. The thickening or structuring agent can be organic (monomeric or polymeric) or inorganic and is usually chosen depending on the physical nature of the liquid phase to be thickened or structured, such as whether it is hydrophobic or hydrophilic. The amount is normally selected in order to attain the desired viscosity of the liquid or cream or desired resistance to penetration of a solid containing the PPAR fatty acid or precursor thereof in accordance with the present invention.
The thickener or structurant can be any of a number of materials, including, for example, waxy structurants for a formulation containing a water-immiscible phase including hydrogenated vegetable oil, hydrogenated castor oil, fatty acids, such as 12-hydroxystearic acid (12-HSA), or ester or amide derivatives of such acids, beeswax, paraffin wax, microcrystalline waxes, silicone wax, and fatty alcohols, such as stearyl alcohol. The structurant can also be a fibre-forming gellant, of which 12-HSA is an example. Other examples include N-acyl amino acid amides and esters, including particularly GP-1 (N-Lauroyl-L-glutamic acid di-n-butylamide), lanosterol, combinations of a sterol and a sterol ester, such as especially xcex2-sitosterol and "khgr"-oryzanol, a polyesterified cellobiose, especially with a C8 to C10 aliphatic acid, threitol esters or and selected secondary amides of di or tri basic carboxylic acids, (eg 2-dodecyl-N,Nxe2x80x2-dibutylsuccinimide) by themselves or in combination.
Polymeric materials for thickening include polymers such as polyamides, hydroxypropylcellulose, and natural or synthetic gums, such as polyglycerides including agar, agarose, pectin, or guars or mixtures or combinations thereof. One class of materials worthy of attention for thickening a water-immiscible phase comprises derivatives of hydrolysed starch or other polysaccharides, including in particular esterified dextrins, such as dextrin palmitate. A further class of polymers that is particularly directed to structuring an oil phase containing a silicone oil comprises polysiloxane elastomers. Suspending agents such as silicas or clays such as bentonite, montmorillonite or hectorite, including those available under the trademark Bentone can also be employed to thicken liquid compositions according to the invention. The composition can be thickened with non-polymeric organic gellants, including selected dibenzylidene alditols (eg dibenzylidene sorbitol).
The amount of structurant or thickening agent that can be employed in the invention compositions will depend upon the viscosity of a fluid formulation or extend of hardness of a solid formulation that the producer wishes to attain. The amount to be employed will in practice also vary depending on the chemical nature of the structurant or thickening agent. In many instances, the amount of structurant or thickening agent will be selected in the range of from 0.1 to 25 wt %, and particularly from 1 to 15 wt %.
The composition according to the invention can optionally comprise other ingredients, in addition to those already identified, depending on the nature and form of the finished product.
Other ingredients contemplated within the personal deodorant or antiperspirants art can also be included in the compositions according to the invention. These include, for example, surfactants/wash-off agents, fillers, fragrances, antioxidants, preservatives and colouring agents. Such ingredients and their amounts of use are usually selected according to the physical and chemical form of the cosmetic composition.
Surfactants can comprise optionally up to 15%, more commonly up to 5% by weight of the total product, and are particularly useful in formulating emulsion antiperspirant or deodorant compositions, for example for use as pump spray or roll-on formulations. However for other product types, it is preferred that the composition contains less than about 8% by weight of surfactants. Non-ionic surfactants are particularly preferred. It is often convenient to select a mixture of surfactants, such as one having a comparatively high HLB value, eg 8 to 18, and one having a comparatively low HLB value, eg 2 to 8, which can be introduced in suitable relative proportions to to attain an average HLB value of about 6 to 12.
Many suitable nonionic surfactants are selected from nonionic esters, ethers or amine oxides having an appropriate HLB value. Many preferred ionic surfactants comprise a polyoxyalkylene moiety, especially a polyoxyethylene moiety eg 2 to 80, especially 5 to 60 oxyethylene units, or possibly with a polyoxypropylene content, to provide hydrophilicity. Other moieties providing hydrophilicity include polyhydric alcohols such as sorbitol or glycerol. The hydrophobic moiety is commonly derived from aliphatic alcohols or acids or amines containing about 8 to 50 carbons and particularly 10 to 30 carbons. Examples of suitable nonionic surfactants include ceteareth-10 to -25, ceteth-10 to -25, steareth-10 to -25, and PEG-15 to -25 stearate or PEG-8 distearate. Other suitable examples include C10-C20 fatty acid mono, di or tri-glycerides. Further examples include C18-C22 fatty alcohol ethers of polyethylene oxides (8 to 12 EO).
Examples of surfactants which typically have a low HLB value, often from 2 to 8, can comprise mono or possibly di fatty acid esters of polyhydric alcohols such as glycerol, sorbitol, erythritol or trimethylolpropane, including cetyl, stearyl arachidyl and behenyl derivatives.
Fillers can comprise up to about 20%, more commonly up to 10% of the base composition and can act as supports for liquid ingredients. Suitable fillers include aluminium stearate, aluminium tri-stearate, calcium stearate, talc or finely divided polyethylene, an example of which is ACUMIST B18. The latter can also enhance skin feel properties.
Fragrances, when present, typically comprise up to about 4% of the total product and often from 0.1 to 1.5%.
Colouring agents antioxidants such as ascorbic acid and tocopherol and preservatives such as C1 to C3 alkyl parabens can be added as desired.
Other optional ingredients are other cosmetic adjuncts conventionally employed or contemplated for employment in antiperspirant or deodorant products.
The ingredients which can optionally be present in the composition carrier can conveniently form the balance of the composition.
Propellants commonly employable in aerosol compositions herein commonly comprise hydrocarbons or halohydrocarbons such as fluorohydrocarbons, having a boiling point of below 10xc2x0 C. and especially those with a boiling point below 0xc2x0 C. It is especially preferred to employ liquified hydrocarbon gases, and especially C3 to C6 hydrocarbons, including propane, isopropane, butane, isobutane, pentane and isopentane and mixtures of two or more thereof. Preferred propellants are isobutane, isobutane/isopropane, isobutane/propane and mixtures of isopropane, isobutane and butane. Other or additional propellants include fluorinated low molecular weight hydrocarbons. Yet still other propellants can include volatile ethers or carbon dioxide.
The relative weight proportions of propellant and base composition is often selected at least 40:60 and particularly at least 60:40. The proportions in many embodiments are up to 99:1 and particularly up to 95:1. Commonly, proportions are selected in the range of at least 70:30 and in the same or other formulations the proportions are up to 90:10.
Compositions according to the invention can be provided in any form of a product suited to or adapted for topical application to human skin, and is usually contained in a suitable holder or dispenser to enable it to be applied to the selected area of the skin, particularly the underarm, where control of perspiration and/or deodorancy is desired.